Veeam Backup for Microsoft 365 repository and ReFS 64K volume

[massimiliano.rizzi]

Hello Community and good day,

please consider the following scenario.

From a Veeam perspective, one of our customers is currently using an all-in-one physical Microsoft Windows server acting as the Veeam Backup & Replication server and primary backup repository, which represents the target for all Primary Backup Jobs.

This server is pretty beefy with 16 cores (32 threads), 128GB of RAM and a 50TB ReFS disk volume as the Veeam repository. The ReFS allocation unit size is 64 KB.

Last year we installed on the same machine Veeam Backup for Microsoft 365 side by side with Veeam Backup & Replication. The Veeam Backup for Microsoft 365 repository is currently hosted on a 64KB NTFS volume backed by an iSCSI LUN from an old QNAP NAS. Everything works with no issues at the moment.

We would like to get rid of this old QNAP NAS and, as result, we are looking to move the Veeam Backup for Microsoft 365 repository and all of the existing data inside the 50TB ReFS disk volume mentioned above side by side with Veeam Backup & Replication backup chains.

Based on my understanding, ReFS 64K might present some issues when used as the Veeam Backup for Microsoft 365 repository. It seems that it is required to disable the integrity feature to avoid potential corruption, which might not be desirable for Veeam Backup & Replication backup chains stored on the same volume.

Is my understanding correct ? Any suggestions and thoughts will be greatly appreciated.

Thanks!

Massimiliano

[HannesK]

Hello,
where did you read about potential corruption? I know the recommendation from the best practice guide, but REFS itself is supported as mentioned in the user guide

If the hardware allows it, I would probably just add more disks to the server.

Best regards,
Hannes

[massimiliano.rizzi]

Hi there Hannes,

thank you for your reply. It is very much appreciated.

I read about potential corruption which requires the integrity feature to be disabled here https://community.veeam.com/discussion- ... ation-2219.

We currently have around 20TB free on the 50TB ReFS disk volume used as the Veeam Backup & Replication repository, so as long as ReFS 64K file system is supported we might just be good to go.

Thanks!

Massimiliano

[Mike Resseler]

The standard repository in VB365 is a jet database which is the same engine used in Microsoft Exchange. ReFS with 64K file system is even recommended. Disabling integrity streams is recommended, but the reason for the recommendation is performance.

If integrity streams are enabled, all write operations become allocate-on-write operations. This avoids any read-modify-write bottlenecks since ReFS doesn’t need to read or modify any existing data but file data frequently becomes fragmented, which delays reading.

Depending on the workload and underlying storage of the system, the computational cost of computing and validating the checksum can cause IO latency to increase which will be the case with a running database. So I would advise to turn it off.

[massimiliano.rizzi]

The standard repository in VB365 is a jet database which is the same engine used in Microsoft Exchange. ReFS with 64K file system is even recommended. Disabling integrity streams is recommended, but the reason for the recommendation is performance.

If integrity streams are enabled, all write operations become allocate-on-write operations. This avoids any read-modify-write bottlenecks since ReFS doesn’t need to read or modify any existing data but file data frequently becomes fragmented, which delays reading.

Depending on the workload and underlying storage of the system, the computational cost of computing and validating the checksum can cause IO latency to increase which will be the case with a running database. So I would advise to turn it off.

Hi there Mike,

thank you very much for your reply and for the information.

Regards,

Massimiliano

[HannesK]

Hello,

I read about potential corruption which requires the integrity feature to be disabled here https://community.veeam.com/discussion- ... ation-2219.

ok, the answer is now also there why the misunderstanding came up

I also asked the authors of the best practice guide to clarify / simplify wording.

Best regards,
Hannes

[HannesK]

the best practice guide was updated and it now states that the recommendation for disabling integrity streams is because of performance